Systems and methods for removing mercury from emissions

ABSTRACT

The present technology is generally directed to systems and methods for removing mercury from emissions. More specifically, some embodiments are directed to systems and methods for removing mercury from exhaust gas in a flue gas desulfurization system. In one embodiment, a method of removing mercury from exhaust gas in a flue gas desulfurization system includes inletting the gas into a housing and conditioning an additive. In some embodiments, conditioning the additive comprises hydrating powder-activated carbon. The method further includes introducing the conditioned additive into the housing and capturing mercury from the gas.

TECHNICAL FIELD

The present technology is generally directed to systems and methods forremoving mercury from emissions. More specifically, some embodiments aredirected to systems and methods for removing mercury from exhaust gas ina flue gas desulfurization system.

BACKGROUND

Many industrial processes utilize emissions treatment systems to reducethe dissemination of various pollutants. Mercury, for example, isconsidered to be a toxic pollutant and its containment is heavilyregulated. One of the most effective methods for removing pollutantssuch as mercury from industrial emissions is a treatment using activatedcarbon.

Activated carbon is a form of carbon processed to be riddled with small,low-volume pores that increase the surface area available for adsorptionor chemical reactions. Powder activated carbon (PAC) is a particulateform of activated carbon, typically having fine granules less than 1.0mm in size with an average diameter between 0.15 and 0.25 mm. PAC thushas a large surface to volume ratio with a small diffusion distance. Inmercury treatment systems, PAC can adsorb vaporized mercury from fluegas and then be collected with fly ash in the treatment facility'sparticulate collection device, such as a bag house. However, PAC issomewhat hydrophilic and can compete for moisture with other compoundsin an emissions treatment system.

For example, lime is used to remove acidic gases, particularly sulfurdioxide, from flue gases. In dry lime scrubbing treatments, lime isinjected directly into flue gas to remove sulfur dioxide. A sulfurdioxide and lime contact zone, such as a spray dryer, provides space formixing hot flue gas and lime slurry that is sprayed through an atomizeror nozzle. The lime slurry absorbs sulfur dioxide. The water in the limeslurry is then evaporated by the hot gas. A portion of the dried,unreacted lime and its reaction products fall to the bottom of thecontact zone and are removed. The flue gas then flows to a particulatecontrol device (e.g., the bag house) to remove the remainder of the limeand reaction products.

Because of PAC's moisture-competitive quality, emissions treatmentsystems utilizing both PAC and lime slurry may require significantlymore lime slurry to adequately remove sulfur dioxide as compared tosystems not using PAC. Accordingly, there exists a need to improve theefficient control and treatment of pollutants such as mercury and sulfurdioxide within a single system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an emissions handling systemconfigured in accordance with embodiments of the technology.

FIG. 2 is a schematic illustration of an additive slurry systemconfigured in accordance with embodiments of the technology.

FIG. 3 is an isometric, partially cut-away view of a silo feed systemconfigured in accordance with embodiments of the technology.

FIG. 4 is a schematic illustration of a conditioner silo configured inaccordance with embodiments of the technology.

FIG. 5 is a block diagram illustrating a method of removing mercury fromexhaust gas in a flue gas desulfurization system in accordance withembodiments of the technology.

FIG. 6 is a block diagram illustrating a method of controlling amoisture content of fly ash in a bag house in accordance withembodiments of the technology.

DETAILED DESCRIPTION

The present technology is generally directed to systems and methods forremoving mercury from emissions. More specifically, some embodiments aredirected to systems and methods for removing mercury from exhaust gas ina flue gas desulfurization system. In one embodiment, a method ofremoving mercury from exhaust gas in a flue gas desulfurization systemincludes inletting the gas into a housing and conditioning an additive.In some embodiments, conditioning the additive comprises hydratingpowder-activated carbon. The method further includes introducing theconditioned additive into the housing and capturing mercury from thegas.

Specific details of several embodiments of the technology are describedbelow with reference to FIGS. 1-6. Other details describing well-knownstructures and systems often associated with emissions handling and/orcoal processing have not been set forth in the following disclosure toavoid unnecessarily obscuring the description of the various embodimentsof the technology. Many of the details, dimensions, angles, and otherfeatures shown in the Figures are merely illustrative of particularembodiments of the technology. Accordingly, other embodiments can haveother details, dimensions, angles, and features without departing fromthe spirit or scope of the present technology. A person of ordinaryskill in the art, therefore, will accordingly understand that thetechnology may have other embodiments with additional elements, or thetechnology may have other embodiments without several of the featuresshown and described below with reference to FIGS. 1-6.

FIG. 1 is a schematic illustration of an emissions handling system 100configured in accordance with embodiments of the technology. In severalembodiments, the system 100 is an air pollution control systemconfigured to handle, process, or contain emissions from a coalprocessing system, such as coke oven flue gases from a heat recoveryplant. In the illustrated embodiment, for example, the emissions canpass from a heat recovery steam generator, or HRSG, 102. The emissionscan initially contain various pollutants such as mercury. In furtherembodiments, the emissions can be generated in another mineralprocessing system, a power plant, a trash to steam plant, a carbon alloyprocessing system, a dry sulfur removal system, a hot ash circulator, orother similar system.

In some embodiments, the emissions pass from the HRSG 102 to acontact/mixing zone 104. The contact zone 104 can comprise any type offlow passageway or scrubber used to remove particulate and/or gases fromthe emissions. In some embodiments, the contact/mixing zone 104comprises one or more of a riser, flow passageway, sulfur dioxideremoval vessel, lime introduction vessel, Spray Dry Absorber (SDA),Circulating Fluidized Bed (CFB), Circulating Dry Scrubber (CDS), GasSuspension Absorber (GSA), Dry Flue Gas Desulphurization (DFGD) System,or Enhanced All Dry Scrubber (EAD).

Upon exiting the contact zone 104, the emissions can pass to a bag house106, fabric filter, or similar air pollution control device. In someembodiments, the emissions pass through a cyclone and/or electrostaticprecipitator prior to entering the bag house 106. Upon exiting the baghouse 106, the emissions can be pulled by an induced draft (ID) fan 108and evaluated by a Continuous Emissions Monitoring System (CEMS) 110and/or exit to the atmosphere via a main stack 112. In variousembodiments, the CEMS 110 can monitor levels of mercury, sulfur dioxide,nitrogen oxides, carbon monoxide, carbon dioxide, hydrogen chloride,airborne particulate matter, volatile organic compounds, oxygen, and/orother parameter. The CEMS 110 can include a sensor and emissions pathwayredirection mechanism configured to redirect the emissions back throughthe contact zone if a sensed parameter doesn't satisfy a desiredemissions level. In further embodiments, the system 100 can includeadditional or alternate sensors further upstream or downstream in theemissions pathway. For example, in some embodiments, tests for otherfactors such as dew point 114, Approach to Saturation Temperature (AST)set point 116, outlet temperature 118, pressure, water partial pressure,mercury level, or other factor can be made along the emissions pathway.These testing points can be at other locations in the system 100 thanthose illustrated in FIG. 1. For example, in other embodiments, setpoint 116 is measured at the outlet of the contact/mixing zone 104 orthe bag house 106. The level of any of these or other parameters can beadjusted to optimize pollutant removal while maintaining systemfunctionality and throughput. In still further embodiments, the system100 can redirect the emissions to an upstream point for further cleaningdepending on a parameter reading.

In several embodiments, the system 100 can include one or more entrypoints for a conditioned additive. The additive can be selected tocapture and/or oxidize mercury or otherwise treat other particulate inthe emissions stream. In several embodiments, for example, the additivecomprises non-brominated or brominated PAC. In further embodiments, theadditive can comprise non-PAC carbon-based materials, promoted PAC,modified PAC, hydrogen bromide, dry absorbents, amended silicate,anhydrous hydrophilic materials, or other suitable materials. PAC can beconsidered a hydrophobic material having slight hydrophilicity; in someembodiments, other materials having similar characteristics can be used.

As will be described in further detail below, conditioning the additivecan comprise various procedures that alter the behavior of the additivetoward the emissions. For example, the conditioning can comprisehydrating the additive (e.g., with water or other substance), applyingsteam or heat to the additive, hydrating and then drying the additive,introducing the additive into a slurry, or other steps. The additive canbe conditioned on site (e.g., during introduction or within an emissionshousing, bag house or pathway) or can be conditioned prior tointroduction. In a particular embodiment, the additive is conditionedimmediately prior to introduction to the bag house 106. In someembodiments, the additive can be conditioned in situ and theconditioning agent can be preferential to the additive over othersubstances in the vicinity. In some embodiments, the additive can beselected and/or conditioned to control the moisture of fly ash in thebag house 106. For example, non-conditioned, dry PAC would bemoisture-preferential in the bag house 106. However, by conditioning PACadditive through hydration, there can be sufficient moisture remainingin the fly ash to ensure sulfur dioxide removal by the lime. In someembodiments, the fly ash moisture content can be kept between about 1%and 7%, and the additive can be conditioned (i.e., hydrated) accordinglyto achieve this level. In other embodiments, the fly ash can be hydratedor otherwise conditioned, which makes it less susceptible to the PACremoving moisture. In some embodiments, the fly ash moisture content canbe affected by the means/timing of additive conditioning. In someembodiments, the additive is introduced with a carrier. In still furtherembodiments, the additive is combined with a surfactant to keep theadditive in suspension.

In operation, the additive can be introduced at one or more differentpoints along the emissions pathway in the system 100. These variousadditive introduction points are illustrated in broken line in FIG. 1.In further embodiments, the additive can be introduced at multiplelocations in the emissions pathway, either simultaneously orselectively. In some embodiments, the additive is introduced at point122 in conjunction with a treatment substance such as lime slurry 120.As discussed above, the lime slurry 120 can be introduced to theemissions (for example, via an atomizer, throat, or nozzle) to removesulfur dioxide from the emissions. In further embodiments, the additivecan be introduced to the emissions pathway separately from the limeslurry injection (either upstream or downstream, such as at introductionpoint 124). In still further embodiments, the additive can be introducedvia a supply line at point 126 in conjunction with a dilution material,such as dilution water 128. In yet another embodiment, the additive isadded directly into the contact zone 104. While FIG. 1 illustrates thatthe additive introduced at introduction points 122, 124 and 126 is PACconditioned on-site (e.g., hydrated at or proximate to the introductionpoint), in further embodiments the additive comprises other suitablematerials and/or can be preconditioned (e.g., pre-hydrated and dried).

In still further embodiments, the additive is introduced downstream ofthe contact zone 104 at introduction point 130. In yet anotherembodiment, the additive is introduced in the bag house 106 atintroduction point 132 (e.g., the additive can be introduced at aninlet, an outlet, or into one or more individual bag house cells). Insome embodiments, the additive is introduced after a cyclone orelectrostatic precipitator proximate to the bag house 106 inlet. Inseveral embodiments where the additive is introduced in or adjacent tothe bag house 106, the additive is dried or partially dried so as to notintroduce excess fluid to the filtration bags in the bag house 106. Inother embodiments, the additive is conditioned in situ in the bag house106 (e.g., moisture/steam and additive are added to the bag house 106),and the moisture can be preferentially absorbed by the additive. WhileFIG. 1 illustrates that the additive introduced at introduction points130 and 132 is preconditioned PAC (e.g., pre-hydrated and dried), infurther embodiments the additive comprises other suitable materialsand/or can be conditioned in situ. Further, the additive can beintroduced in response to a sensed condition (e.g., an additiveintroduction mechanism can be in communication with a sensor). In someembodiments, the additive is introduced in response to a sensed mercurylevel. In other embodiments, the additive is introduced continuously,dynamically, or at a pre-set timing interval. In various embodiments,the additive introduction can be pressurized or non-pressurized (e.g.gravity-fed).

FIG. 2 is schematic illustration of an additive slurry system 200configured in accordance with embodiments of the technology. The slurrysystem 200 can be used to supply a conditioned additive to the emissionshandling system 100 illustrated in FIG. 1. For example, in someembodiments, the slurry system 200 can be used to condition an additivefor introduction to the emissions handling system 100 at points such as122, 124, or 126, or other location shown in FIG. 1.

The slurry system 200 comprises an additive silo 202 configured toaccept raw additive such as PAC. As will be described in further detailbelow with reference to FIG. 3, the additive silo 202 contains or iscoupled to a silo feed system 204 configured to break up and/or meteradditive for admixture with a conditioning agent (e.g., water or otherfluid). The conditioning agent can be contained in one or moreconditioner (e.g., hydration) silos or wetting cones 206. After theadditive from the additive silo meets the conditioner from the wettingcones 206, the additive becomes conditioned and can be stored in aconditioned additive silo 208. In one embodiment, the conditionedadditive silo 208 is configured to store hydrated PAC slurry. Theconditioned additive can be metered for delivery to the emissionspathway discussed above with reference to FIG. 1 via one or moreconditioned additive delivery lines 210.

FIG. 3 is an isometric, partially cut-away view of the silo feed system204 of FIG. 2, configured in accordance with embodiments of thetechnology. The silo feed system 204 includes an arch breaker 302configured to break up and/or meter the additive. The additive can beredirected at region 306 toward conditioner silos (e.g., wetting cones206 in FIG. 2) via one or more screw feeders 304. In some embodiments,the screw feeders 304 compact or meter the additive. The screw feeders304 can operate simultaneously or redundantly during system repairs. Theadditive can processed by the silo feed system 204 at a selected rate toachieve the desired degree of mercury removal. For example, in someembodiments, PAC can be passed through the silo feed system 204 at arate of about 10 to 250 pounds per hour. In a particular embodiment, thePAC is processed at a rate of about 90 pounds per hour.

FIG. 4 is a schematic illustration of the conditioner silo 206configured in accordance with embodiments of the technology. Theconditioner silo 206 includes an inlet 402 configured to receiveadditive from the silo feed system 204 (e.g., from the screw feeder 304shown in FIG. 3). Metered quantities of conditioning agent (e.g., water)are introduced to the additive from a conditioning agent supply line404. The additive and conditioning agent are admixed in a hopper orwetting cone 406 and passed to a conditioned additive silo (e.g., theconditioned additive silo 208 shown in FIG. 2). The additive andconditioning agent can be selected in respective quantities to achieve adesired level of dilution. For example, in one embodiment, water and PACare combined to form an approximately 1%-10% solution of hydrated PAC.In a particular embodiment, water and PAC are combined to form anapproximately 1%-7% solution. The conditioned additive is ready forintroduction to the emissions pathway of the emissions handling system100 shown in FIG. 1 via one or more dedicated or shared supply lines.

While FIGS. 2 through 4 illustrate a particular set of devices forconditioning (i.e., hydrating) an additive, in further embodimentsnumerous other conditioning devices and methods can be used. Forexample, heaters, coolers, steam generators, dryers, nozzles, atomizers,throat nozzles, converging and/or diverging nozzles, metering devices,compactors, or other devices can be used individually or in combinationto condition, initialize, or otherwise prepare one or more additives forintroduction to the emissions handling system 100. Further in someembodiments, one or more conditioned or non-conditioned additives can beadded in combination at the same or multiple spots in the system 100.

FIG. 5 is a block diagram illustrating a method 500 of removing mercuryfrom exhaust gas in a flue gas desulfurization system in accordance withembodiments of the technology. In some embodiments, the method 500includes inletting the gas into a flue gas desulfurization systemhousing 510. The method 500 further includes conditioning an additive520. The conditioning can comprise hydrating, drying, heating, etc. Inparticular embodiments, conditioning the additive comprises hydratingPAC with water. In another particular embodiment, the conditioningcomprises drying previously-hydrated PAC. The drying can compriseremoving free water, physisorbed water, or chemisorbed water.

The method 500 further includes introducing the conditioned additiveinto the housing 530. The introduction can be done by a gravity feed,pump, drip mechanism, nozzle, throat, atomizer, or other deliverydevice. In some embodiments, the introduction comprises automaticallycontrolling or modifying a dilution percentage of the hydrated PAC. Infurther embodiments, the introduction comprises automatically modifyinga timing of introduction. In some embodiments, the automaticmodification of introduction can be in response to a sensed temperature,mercury level, dew point, approach to saturation temperature, waterpartial pressure, humidity, or other condition. In still furtherembodiments, the conditioned additive can be introduced at a pre-settiming interval. The method 500 additionally includes capturing mercuryfrom the gas with the conditioned additive 540.

FIG. 6 is a block diagram illustrating a method 600 of controlling amoisture content of fly ash in a bag house in accordance withembodiments of the technology. The method 600 includes conditioning anadditive 610 (e.g., PAC) in any of the manners described above. Theadditive is introduced to emissions within a housing 620. In variousembodiments, the additive can be conditioned in situ (e.g., by combiningthe additive with liquid water or steam in the housing with theemissions) or prior to introduction to the emissions in the housing(e.g., by pre-hydrating and drying the additive). In some embodiments,the introduction comprises pumping the additive into a flue-gasdesulfurization system.

The emissions are passed to a bag house having flay ash therein 630. Themethod 600 further includes controlling a moisture content of the flyash in the bag house in response to the introducing 640. For example, insome embodiments, the type of additive, the method of additiveconditioning, and/or the means of additive introduction to the emissionscan allow a user to control the moisture content in the fly ash and/oroperate the system to achieve a desired level of moisture.

EXAMPLES

1. A method of removing mercury from exhaust gas in a flue gasdesulfurization system, the method comprising:

-   -   inletting the gas into a housing;    -   conditioning an additive;    -   introducing the conditioned additive into the housing; and    -   capturing mercury from the gas.

2. The method of example 1 wherein conditioning the additive comprisesconditioning powder activated carbon.

3. The method of example 2 wherein conditioning powder activated carboncomprises hydrating the powder activated carbon with water.

4. The method of example 3 wherein hydrating the powder activated carboncomprises forming an approximately 1%-7% solution of hydrated powderactivated carbon.

5. The method of example 3, further comprising dryingpreviously-hydrated powder activated carbon, wherein introducing theconditioned additive comprises introducing the dried,previously-hydrated powder-activated carbon.

6. The method of example 1 wherein introducing the conditioned additivecomprises introducing the conditioned additive via an atomizer, throat,or nozzle.

7. The method of example 1 wherein introducing the conditioned additiveinto the housing comprises automatically modifying a dilution percentageof the conditioned additive.

8. The method of example 1, further comprising sensing at least one of amercury level, temperature or humidity condition.

9. The method of example 8 wherein introducing the conditioned additivecomprises automatically introducing the conditioned additive in responseto the sensed mercury level.

10. The method of example 1 wherein introducing the conditioned additivecomprises introducing the conditioned additive continuously or at apre-set timing interval.

11. A method, comprising:

-   -   conditioning an additive;    -   introducing the conditioned additive to emissions within a        housing;    -   passing the emissions to a baghouse, the baghouse having fly ash        therein; and    -   controlling a moisture content of the fly ash in the baghouse in        response to the introducing.

12. The method of example 11, further comprising hydrating the fly ash.

13. The method of example 11 wherein conditioning the additive compriseshydrating and at least partially drying the additive.

14. The method of example 11 wherein conditioning the additive compriseshydrating the additive within the housing.

15. The method of example 11 wherein conditioning the additive compriseshydrating the additive prior to introducing the additive into thehousing.

16. The method of example 11 wherein conditioning the additive comprisesintroducing steam or water to the additive.

17. The method of example 11 wherein introducing the conditionedadditive to emissions comprises pumping the conditioned additive into aflue-gas desulfurization system.

18. A flue gas desulfurization system, comprising:

-   -   a source of emissions, the emissions including mercury;    -   a housing comprising an inlet in communication with the source,        and an outlet in communication with a baghouse;    -   a source of conditioned additive; and an introducer configured        to introduce the conditioned additive to the housing.

19. The system of example 18 wherein the introducer comprises anatomizer, throat, or nozzle configured to inject the conditionedadditive to the housing.

20. The system of example 18, further comprising a sensor configured tosense at least one of a mercury level, temperature, dew point, orpressure, wherein the sensor is in communication with the introducer.

21. The system of example 18 wherein the source of the emissionscomprises at least one of a coke processing system, a power plant, atrash to steam plant, a carbon alloy processing system, a dry sulfurremoval system, or a hot ash circulator.

22. The system of example 18 wherein the source of the conditionedadditive comprises:

-   -   an additive silo;    -   a hydration silo; and    -   a slurry silo coupled to the introducer and configured to        receive material from the additive silo and the hydration silo.

23. The system of example 22, further comprising a breaker positioned inthe additive silo and configured to break up the additive.

24. The system of example 22 wherein the hydration silo comprises agenerally-conical shape and is configured to meter fluid introduction tothe slurry silo.

25. The system of example 18 wherein the introducer comprises a supplyline in fluid connection with the source of conditioned additive and asource of dilution water.

26. The system of example 18 wherein the introducer comprises a supplyline in fluid connection with the source of conditioned additive and asource of lime slurry.

27. A method, comprising:

-   -   introducing an additive to emissions within a bag house; the bag        house having fly ash therein;    -   conditioning one or both of the additive or the fly ash; and    -   controlling a moisture content of the fly ash in the bag house.

28. The method of example 27 wherein conditioning one or both of theadditive or the fly ash comprises hydrating one or both of the additiveor the fly ash.

29. The method of example 27 wherein introducing an additive toemissions within a bag house comprises introducing dry powder-activatedcarbon to the emissions within a bag house.

From the foregoing it will be appreciated that, although specificembodiments of the technology have been described herein for purposes ofillustration, various modifications may be made without deviating fromthe spirit and scope of the technology. For example, while theconditioned additive is illustrated as being introduced into variouslocations in the emissions pathway, in further embodiments, theconditioned additive can be introduced further upstream, furtherdownstream, at multiple locations, or by different means than shown.Further, certain aspects of the new technology described in the contextof particular embodiments may be combined or eliminated in otherembodiments. For example, while the conditioned additive is described inseveral embodiments as being hydrated PAC, in further embodiments theconditioned additive can comprise any substance having suitable materialproperties for use in the systems described herein. Moreover, whileadvantages associated with certain embodiments of the technology havebeen described in the context of those embodiments, other embodimentsmay also exhibit such advantages, and not all embodiments neednecessarily exhibit such advantages to fall within the scope of thetechnology. Accordingly, the disclosure and associated technology canencompass other embodiments not expressly shown or described herein.Thus, the disclosure is not limited except as by the appended claims.

We claim:
 1. A method of removing mercury from exhaust gas in a flue gasdesulfurization system, the method comprising: inletting the gas into ahousing; conditioning powder activated carbon by hydrating the powderactivated carbon and increasing a moisture content of the powderactivated carbon; introducing the conditioned powder activated carbon,with the increased moisture content, into a dry scrubber associated withthe housing; and capturing mercury from the gas.
 2. The method of claim1 wherein conditioning powder activated carbon comprises hydrating thepowder activated carbon with water.
 3. The method of claim 2 whereinhydrating the powder activated carbon comprises forming an approximately1%-7% solution of hydrated powder activated carbon.
 4. The method ofclaim 2, further comprising drying previously-hydrated powder activatedcarbon, which removes excess fluid from the powder activated carbon butleaves it with an increased moisture content.
 5. The method of claim 1wherein introducing the conditioned powder activated carbon comprisesintroducing the conditioned powder activated carbon via an atomizer,throat, or nozzle.
 6. The method of claim 1 wherein introducing theconditioned powder activated carbon into the housing comprisesautomatically modifying a dilution percentage of the conditioned powderactivated carbon.
 7. The method of claim 1, further comprising sensingat least one of a mercury level, temperature or humidity condition. 8.The method of claim 7 wherein introducing the conditioned powderactivated carbon comprises automatically introducing the conditionedpowder activated carbon in response to the sensed mercury level.
 9. Themethod of claim 1 wherein introducing the conditioned powder activatedcarbon comprises introducing the conditioned powder activated carboncontinuously or at a pre-set timing interval.
 10. A method of removingmercury from exhaust gas in a flue gas desulfurization system, themethod, comprising: conditioning powder activated carbon by hydratingthe powder activated carbon and increasing a moisture content of thepowder activated carbon; introducing the conditioned powder activatedcarbon to emissions within a housing; passing the emissions to abaghouse, the baghouse having fly ash therein; and the increasedmoisture content of the powder activated carbon controlling a moisturecontent of the fly ash in the baghouse in response to the introducing;and capturing mercury from the emissions.
 11. The method of claim 10,further comprising hydrating the fly ash.
 12. The method of claim 10wherein conditioning the powder activated carbon comprises hydrating andat least partially drying the powder activated carbon.
 13. The method ofclaim 10 wherein conditioning the powder activated carbon compriseshydrating the powder activated carbon within the housing.
 14. The methodof claim 10 wherein conditioning the powder activated carbon compriseshydrating the powder activated carbon prior to introducing the powderactivated carbon into the housing.
 15. The method of claim 10 whereinconditioning the powder activated carbon comprises introducing steam orwater to the powder activated carbon.
 16. The method of claim 10 whereinintroducing the conditioned powder activated carbon to emissionscomprises pumping the conditioned powder activated carbon into aflue-gas desulfurization system.
 17. A flue gas desulfurization system,comprising: a source of emissions, the emissions including mercury; ahousing comprising an inlet in communication with the source, and anoutlet in communication with a baghouse; a source of conditioned powderactivated carbon; wherein the powder activated carbon is conditioned byincreasing a moisture content of the powder activated carbon; and anintroducer configured to introduce the conditioned powder activatedcarbon, with the increased moisture content, to a dry scrubberassociated with the housing.
 18. The system of claim 17 wherein theintroducer comprises an atomizer, throat, or nozzle configured to injectthe conditioned powder activated carbon to the housing.
 19. The systemof claim 17, further comprising a sensor configured to sense at leastone of a mercury level, temperature, dew point, or pressure, wherein thesensor is in communication with the introducer.
 20. The system of claim17 wherein the source of the emissions comprises at least one of a cokeprocessing system, a power plant, a trash to steam plant, a carbon alloyprocessing system, a dry sulfur removal system, or a hot ash circulator.